DESCRIPTION: (Applicant's Abstract) Substance Dependence-PTSD Therapy: A CBT Dismantling Study PTSD is common among addicts. Nevertheless, no standard treatment modality exists for this comorbidity. As part of a previously funded Stage I psychotherapy development grant, an innovative, manual-driven individual psychotherapy was designed using Components of Cognitive Behavioral Coping Skills Therapy (CBCST) for addictions and Stress inoculation therapy and in vivo desensitization for PTSD, among other techniques. This new therapy, Substance Dependence PTSD Treatment (SDPT) has shown promise and feasibility in preliminary testing on measures of PTSD. This promise has, in turn, raised questions as to whether SDPT'S efficacy is purely due to its roots in CBT for addiction, or whether the PTSD-specific component have specific, additional effects. The specific aims, for this Stage lb study, then are to l) Refine and expand CBCST for addictions to accommodate a 20-week, 40-session treatment length from its current 12-week duration: 2) Revise and implement a therapist adherence/competence measure to further differentiate between CBCST therapist behaviors and SDPT therapist behaviors: 3) Using a dismantling strategy, we will conduct a pilot study contrasting SDPT and its parent therapy, CBCST in 36 methadone-maintained PTSD-diagnosed subjects, which will examine whether the PTSD components of SDPT significantly improves upon CBCST in PTSD symptom reduction in mixed-gendered, civilian, mixed-trauma exposed methadone-maintained subjects, in order to determine estimated effect sizes for hypothesized differences and the promise of a full SDPT-CBCST trial: and 4) We will examine treatment-related outcomes at 1- and 3-month posttreatment follow-up timepoints, in order to determine whether short-term differential outcomes between treatment conditions emerge, and if so, to determine estimated effect sizes for such outcomes. Measures of treatment specificity will evaluate hypothesized intermediary steps in the change process (as mediator or moderator variables) which lead to the reduction of drug abuse and PTSD symptoms. A secondary aim will be to examine HIV risk behaviors across conditions to determine if the PTSD-specific components of SDPT further decreases such risk behaviors.